Carburetor



2, 1930. G. M. BICKNELL CARBURETOR Filed May 5. 1927 a //v v/v 70/? eerie BY m ATTORNEY Patented Dec. 2, 1930 PATENT OFFICE", g

",UNITED STATES M. IBIOKNELL. ST. 'LOUIS,.HISSOURI, ASSIGNOB TO CARTER CARBURETOR I CORPORATION, 0] 8'1. LOUIS, VHISSOUBI, A OOBPOBATION OF DELAWARE onauanroa Application filed Kay- 5, 1927. Serial No. 189,085.

Reference is had to the accompan ing drawings which illustrate the preferred orm of the invention, though it is to be. un-' derstood that'the invention is not limited to i the exact details of construction shown and described, as it is obvious that various modifications thereof within the scope of the claims will occur to persons skilled in the art.

In said drawings:

Figure 1 is a view partly in elevation and partly in section of a carburetor constructed in accordance with this invention;

Fig. 2 is'partial plan view of the carburetor shown in Fig. 1, parts being broken away to show other parts more clearly; and,

Figs. 3 and are partial vertical sections taken on the, line 3-4 of Fi 2, showing the relative positions of the cho 'e valve and theair inlet port controlled therewith, the choke valve being shown in dotted lines.

This invention relates to carburetors, and

; it is an object of this invention to provide a carburetor which will be equally as eflicient and economical in operation when used with an air cleaner or other device which causes a restriction of the carburetor air intake as it is when used without such device. It is also an object of this invention to provide a carburetor of the type described which can be to economically manufactured of a few simply constructed parts which will not be easily broken or thrown out of adjustment.

In the drawings, the invention is shown in a carburetor comprising a body 1 having a primary air inlet 2 controlled by a choke valve 4 mounted for operation upon a; shaft 6 I which is journaled in the body walls p rovi'ded 11.6 22, stand pipe and venturi 8 to the mixa passage leads through theventuri 8 to the ing chamber 10 and thence to the intake manifold of the engine.

In the present construction of automobiles,

various devices are be ng used in connection w1th the carburetor, such as crank case ventilators, hot air stoves and air cleaners which. cause a slight restriction ofthe flow of air enterin the carburetor air intake 2. This restrict1on will cause a slightly richer mixture to be delivered from the carburetor unless some method of compensating for it be employed. In the construction shown in the drawing, this is provided for by usin a pressure balance passage, 26 between the an chamher 7 and the float chamber 18. The restriction of the flow of air entering the air chamber 7 causes a slight reduction in the pressure of the air chamber which in turn is, in part, communicated through passage 26 to the float chamberlS, the pressure in the lfloatchamber varying in constant relation to the reduced :air pressure in the air chamber 7 so that as the reduction in pressure in the chamber 7 is increased by the restriction of the air intake 2 there is a corresponding reduction in pressure in the float chamber 18. This reduction in pressure in the float chamber 18 retards the flow of fuel from the float chamber 18 to the carburetor nozzle 22 and prevents the added restriction caused by the air cleaner or other device from affecting the metering characteristicsof the carburetor. With the choke valve 4 provided in the air intake 2 for use in starting and in warming up the motor, an additional air inlet is provided to the float chamber 18 from the atmosphere, in order to prevent pressure in the float chamber '18 equalizing with the pressure in the air chamber when the choke valve is fully closed and stopping the flow of fuel from the carburetor the additional nozzle 22 In the drawings,

assa e 30 is provided extending from the oatc amber 18 to the atmosphere, and passing through a portion of a wall of the body 1 which serves to support an end of the shaft 6 of the choke valve 4'. The end of the choke valve shaft 6 is provided with the port 32 which may be alined with passage 30 to permit the passage of air to the float chamber 18. The port 32 is so placed in the shaft 6 and so proportioned that it will fully open the passage 30 when the choke valve 4 is in closed and nearly closed positions as shown in Fig. 4 and will close the passage 30 when the choke valve 4 is in the fully opened position as shown in Fig. 3. This arrangement permits vof the use of the pressure balance passage 26 for ordinary running when the choke valve 4 is fully opened and a rich mixture is not desired, and for the use of the additional air passage 30 when the choke valve 4 is closed for starting and a richer mixture is desired.

It will be understood that this arrangement may be used in connection with any type of carburetor in which the main air passage is closed to assist in the starting of the motor.

What is claimed is:

1. In a carburetor, a float chamber, an air chamber, a choke valve controlling the admission, of air to said air chamber, an operator for said chake valve, a passage connecting said chambers, another passage from said float chamber to atmosphere and means actuated by said operator for controlling said passage to atmosphere, said means operating reversely to said choke valve.

2. In a carburetor, a float chamber, an air chamber, a choke valve controlling the admission of air to said air chamber, a shaft for said choke valve, a separate passage connecting said chambers, a passage from said float chamber to atmosphere and a port insaid choke valve shaft controlling said passage to atmosphere, said passage being normally closed.

3. In a carburetor, a float chamber, a primary air chamber, a passage leading from the air chamber to the float chamber, a choke valve for varying the amount of air admitted into the air chamber and for varying the air pressure in the float chamber, a normally closed passage for admitting air from the atmosphere to the float chamber, and means controlling the operation of the choke valve and the admission of air from atmosphere to the float chamber to compensate for variations in pressure in the float chamber.

4. In a carburetor, a float chamber, an air inlet, a choke valve in the air inlet, a passage connecting said float chamber and air inlet and through which air passes to normally maintain a pressure in the float chamber commensurate with the position of the choke valve, a passage leading from the atmosphere to the float chamber and normally closed means in said second passage connected to and operative in response to movement of the choke valve to admit atmospheric air into said float chamber to compensate for variations in air pressure therein and in accordance with the position of the choke valve.

5. In a carburetor, a float chamber, a primary air inlet, a passage leading from the air inlet to the float chamber to admit air into the latter to maintain pressure therein, a

choke valve for controlling the admission of air through the inlet an for varying the pressure in the float chamber, a shaft mounting said chokevalve and having a valve at one end thereof, and a normally closed passage controlled by said valve and opened upon movement of said choke valve shaft for admitting atmospheric air to the float chamber commensurate with variation of pressure therein and in accordance with the postion of the choke valve.

6. In a carburetor, a suction conduit having an inlet and an outlet, Valves controlling said inlet and said outlet, a float chamber adapted to contain fuel and air, a fuel conduit leading from below the fuel level in said float chamber and discharging into the mixing conduit between said valves, a port providing communication between said fuel chamber and said mixing conduit, whereby the pressure in said float chamber will be normally slightly decreased by suction from said mixing conduit, and mean for increasing the pressure in said float chamber when said inlet valve is closed.

7. In a carburetor, a suction conduit having an inlet and an outlet, valves controlling said inlet and said outlet, a float chamber adapted to contain fuel and air, a fuel conduit feeding from below the fuel level in said float chamber and discharging into the mixing conduit between said valves, a port providing communication between a point in said fuel chamber above'the fuel level and said mixing conduit, said port being so disposed with relation to said mixing conduit that the pressure in said float chamber will be normally decreased by suction in-said mix ing conduit, and means operated in conjunction with said inlet valve for admitting air at substantially atmospheric pressure into said float chamber when said valve is closed; Ini witness whereof I have hereunto set my han GEORGE M. BICKNELL. 

